Finding the Fourth Proportional to 12,780.30, 17,636.33 and 7,115.27

Step by Step Solution

1. Step 1: Write the proportion equation
   12,780.30 : 17,636.33 = 7,115.27 : x
2. Step 2: Convert to fraction form
   12,780.30/17,636.33 = 7,115.27/x
3. Step 3: Cross multiply
   12,780.30x = 17,636.33 × 7,115.27
4. Step 4: Simplify right side
   12,780.30x = 125,487,214.18
5. Step 5: Solve for x
   x = 125,487,214.18/12,780.30
6. Step 6: Final answer
   x = 9,818.80